Lower Engelberg Tunnel
The longest and busiest motorway tunnel in Baden-Württemberg
![](https://www.ssf-ing.de/wp-content/uploads/2024/06/23.png)
110.000
motor vehicles/day traffic volume
Renovation: no chance for anhydrite
The comprehensive upgrading of the Lower Engelberg Tunnel includes an optimisation and supplementation of the existing operational equipment of the entire tunnel to the current state of the art in accordance with RABT 2016.
Site
Leonberg, Germany
Building contractor/client
Stuttgart Regional Council
Planning period
2017–2022
Service areas
Object planning for civil engineering structures, structural engineering, specialist planning for technical equipment, additional BIM service
Total length
West tube approx. 2,530 m, east tube approx. 2,520 m
Total width
16.80 m
Clear height
8.10 m
Number of tubes
2
- The Lower Engelberg Tunnel near Leonberg is located on the A81 motorway immediately north of the Leonberg junction near Stuttgart
- The tunnel is used by 110,000 vehicles every day and is vital for opening up the greater Stuttgart area
- It was built from 1995 to 1999 as a two-tube tunnel with a length of approx. 2,500 m using the mining construction method
- After almost 20 years of operation, both tunnels show considerable damage over a length of approx. 180 metres in the inner lining and the slot channels in the form of deformations in the area of the anhydrite-bearing rock.
- According to the resistance principle, this requires extensive structural upgrading of the inner shell as a steel/steel composite construction with an additional inner shell
![](https://www.ssf-ing.de/wp-content/uploads/2024/05/000d801fb7825e1ec491d22524e6858d-1091x728.jpeg)
Test image description